Honey solutions with the concentration of 1 g/10 mL
were centrifuged and filtered by a paper filter. Afterwards, 0.5 mL of
the resultant solution were mixed with 2.5 mL of 0.2 mol/L solution
of FolineCiocalteu reagent and 2 mL of sodium carbonate solution
(75 g/L) was added.